Many devices, e.g. portable consumer electronics such as cellphones, media players, and watches, include housings formed from structurally strong and stiff materials such as stainless steel. The strength provided by materials such as stainless steel enables the housings to protect internal components of the consumer electronics, and enhances the durability of such devices.
In some applications, while stainless steel provides desirable strength characteristics for housings, the stainless steel may not provide acceptable cosmetic characteristics. For example, a polished stainless steel surface is often relatively easy to scratch, and a scratched stainless steel surface may be unappealing. Additionally, stainless steel can be at risk of corrosion at or near locations of laser etching. This is because laser etching can cause localized melting of the stainless steel, which can lead to localized regions of lean chrome content and high chrome content when the stainless steel re-solidifies. The lean chrome regions can be susceptible to corrosion.
In order to maintain the look and feel of the stainless steel, while also preventing corrosion in consumer electronic housings, it may be desirable to protect the stainless steel or other metal surface of the housing from damage that would adversely affect outward appearance. Furthermore, it may be desirable that the protection provided to the stainless steel surface does not substantially adversely affect the look and feel of the device.